And before you refer to the pricey 10-18, remember that it requires the same corrections that all UWA zooms do, even the ones that cost twice as much.

this is the price to pay for compacity... more complex engineering design and building... more cost.

If compacity is not important for you, buy a big lense... at equal quality, it will be cheaper. If you need compacity, there are rather no (or so few) equivalent offers on the market... something unic cannot be "expensive" because you cannot compare with any competitors